Can Fibromyalgia be service-connected as secondary to Chronic Fatigue Syndrome (CFS)?

Yes. Under 38 CFR § 3.310, a condition that is caused or aggravated by an already service-connected disability can be granted secondary service connection. Fatigue may coexist or be confused with muscle pain syndromes. You'll need a current Fibromyalgia diagnosis and a medical nexus opinion linking it to your service-connected Chronic Fatigue Syndrome (CFS), the same standard the VA uses for any secondary claim.

What evidence do I need to service-connect Fibromyalgia as secondary to Chronic Fatigue Syndrome (CFS)?

Strong evidence for the underlying Fibromyalgia diagnosis includes: A rheumatologist's or primary care provider's diagnosis; Documentation of tender points identified during a physical exam; A symptom journal or pain log showing the pattern and frequency of flares over time. For the secondary link itself, a nexus letter from a treating provider explaining how Chronic Fatigue Syndrome (CFS) caused or aggravated Fibromyalgia is typically the deciding piece of evidence. If the claim is that a pre-existing Fibromyalgia got worse, include records showing how severe it was before it worsened: VA will not concede aggravation unless the baseline is established by medical evidence created before the worsening began, or by the earliest medical evidence after it (38 CFR 3.310(b)).

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Secondary Condition Claim · DC 5025

Fibromyalgia Secondary to Chronic Fatigue Syndrome (CFS)

A condition caused or aggravated by an already service-connected disability can be granted its own service connection as a secondary condition under 38 CFR § 3.310. Here's how that works for Fibromyalgia when it develops after Chronic Fatigue Syndrome (CFS).

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Why is Fibromyalgia linked to CFS?

Fatigue may coexist or be confused with muscle pain syndromes.

Primary condition · VASRD 6354

Chronic Fatigue Syndrome (CFS)

CFS causes persistent fatigue not improved by rest and worsened by physical or mental activity.

Secondary condition · VASRD 5025

Fibromyalgia

Fibromyalgia is a chronic pain condition marked by widespread musculoskeletal pain and tender points, usually with fatigue, unrefreshing sleep, stiffness and cognitive fog. VA rates it under DC 5025, and the percentage turns on how much of the time the pain is present and whether medication or therapy controls it — not on how many joints are involved.

How does secondary service connection work?

When the service-connected condition caused it: 38 CFR § 3.310(a): “Except as provided in § 3.300(c), disability which is proximately due to or the result of a service-connected disease or injury shall be service connected. When service connection is thus established for a secondary condition, the secondary condition shall be considered a part of the original condition.”
When it made an existing condition worse: 38 CFR § 3.310(b): “Any increase in severity of a nonservice-connected disease or injury that is proximately due to or the result of a service-connected disease or injury, and not due to the natural progress of the nonservice-connected disease, will be service connected.” VA will not concede aggravation unless medical evidence establishes the baseline severity; it then deducts that baseline, and any natural progress, from the current level.
How strong the evidence for the link has to be: 38 U.S.C. § 5107(b): “When there is an approximate balance of positive and negative evidence regarding any issue material to the determination of a matter, the Secretary shall give the benefit of the doubt to the claimant.” When the positive and negative evidence on the link is in approximate balance, VA gives the benefit of the doubt to the veteran.
What VA means by reasonable doubt: 38 CFR § 3.102: “By reasonable doubt is meant one which exists because of an approximate balance of positive and negative evidence which does not satisfactorily prove or disprove the claim.”
A statute that asks for an “at least as likely as not” medical opinion: 38 U.S.C. § 1168(a)(1)(B): “obtain a medical opinion (to be requested by the Secretary in connection with the medical examination under subparagraph (A)) as to whether it is at least as likely as not that there is a nexus between the disability and the toxic exposure risk activity.” § 1168 covers exams and opinions in toxic-exposure claims. For any claim for VA benefits, § 5107(b) above gives the veteran the benefit of the doubt when the evidence is in approximate balance.

How is Fibromyalgia rated as a secondary condition?

If Fibromyalgia was caused by the service-connected condition, VA rates it on its own severity under its own diagnostic code, as part of the original condition (38 CFR 3.310(a)). If Fibromyalgia existed first and the service-connected condition made it worse, VA compensates only the worsening: it rates the baseline and current severity and deducts the baseline, and any natural progression, from the current level (38 CFR 3.310(b)). Read 38 CFR § 3.310.

Rating	Criteria
40%	With widespread musculoskeletal pain and tender points, with or without associated fatigue, sleep disturbance, stiffness, paresthesias, headache, irritable bowel symptoms, depression, anxiety, or Raynaud's-like symptoms: that are constant, or nearly so, and refractory to therapy
20%	With widespread musculoskeletal pain and tender points, with or without associated fatigue, sleep disturbance, stiffness, paresthesias, headache, irritable bowel symptoms, depression, anxiety, or Raynaud's-like symptoms: that are episodic, with exacerbations often precipitated by environmental or emotional stress or by overexertion, but that are present more than one-third of the time
10%	With widespread musculoskeletal pain and tender points, with or without associated fatigue, sleep disturbance, stiffness, paresthesias, headache, irritable bowel symptoms, depression, anxiety, or Raynaud's-like symptoms: that require continuous medication for control

Example combined rating

40% Chronic Fatigue Syndrome (CFS) + 20% Fibromyalgia = 50% combined

The VA combines ratings with Table I of 38 CFR 4.25, not simple addition: 40% and 20% combine to a Table I value of 52%, which VA converts to a 50% combined rating under 38 CFR 4.25, not 60%. These figures are illustrative; your actual rating for each condition depends on your own evaluation.

What evidence does a secondary Fibromyalgia claim need?

•A rheumatologist's or primary care provider's diagnosis.
•Documentation of tender points identified during a physical exam.
•A symptom journal or pain log showing the pattern and frequency of flares over time.

Common questions about Fibromyalgia secondary to CFS

Can Fibromyalgia be service-connected as secondary to Chronic Fatigue Syndrome (CFS)?: Yes. Under 38 CFR § 3.310, a condition that is caused or aggravated by an already service-connected disability can be granted secondary service connection. Fatigue may coexist or be confused with muscle pain syndromes. You'll need a current Fibromyalgia diagnosis and a medical nexus opinion linking it to your service-connected Chronic Fatigue Syndrome (CFS), the same standard the VA uses for any secondary claim.
What VA rating can I get for Fibromyalgia as a secondary condition?: Fibromyalgia is rated under VASRD diagnostic code 5025. Possible VA ratings for Fibromyalgia are 40%, 20%, 10%, 0%. The 0% level comes from 38 CFR 4.31, which assigns it wherever no compensable level is met. If Fibromyalgia was caused by the service-connected condition, VA rates it on its own severity under its own diagnostic code, as part of the original condition (38 CFR 3.310(a)). If Fibromyalgia existed first and the service-connected condition made it worse, VA compensates only the worsening: it rates the baseline and current severity and deducts the baseline, and any natural progression, from the current level (38 CFR 3.310(b)).
How does a secondary Fibromyalgia claim affect my combined VA rating?: The VA doesn't add ratings together. With example figures of 40% for Chronic Fatigue Syndrome (CFS) and 20% for Fibromyalgia: 40% and 20% combine to a Table I value of 52%, which VA converts to a 50% combined rating under 38 CFR 4.25, not 60%. Approving Fibromyalgia as secondary still typically raises your overall combined rating and monthly compensation.
What evidence do I need to service-connect Fibromyalgia as secondary to Chronic Fatigue Syndrome (CFS)?: Strong evidence for the underlying Fibromyalgia diagnosis includes: A rheumatologist's or primary care provider's diagnosis; Documentation of tender points identified during a physical exam; A symptom journal or pain log showing the pattern and frequency of flares over time. For the secondary link itself, a nexus letter from a treating provider explaining how Chronic Fatigue Syndrome (CFS) caused or aggravated Fibromyalgia is typically the deciding piece of evidence. If the claim is that a pre-existing Fibromyalgia got worse, include records showing how severe it was before it worsened: VA will not concede aggravation unless the baseline is established by medical evidence created before the worsening began, or by the earliest medical evidence after it (38 CFR 3.310(b)).

Primary condition

Full Chronic Fatigue Syndrome (CFS) guide

Secondary condition

Full Fibromyalgia guide

Every secondary condition, grouped by condition

Other secondary conditions of Chronic Fatigue Syndrome (CFS)

Major Depressive Disorder

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